A known tandem-type image forming apparatus includes a plurality of process cartridges spaced in a line, and is configured to print a color image at once.
The image forming apparatus is configured such that toner cartridges can be removed and replaced from the top of the apparatus. Thus, the image forming apparatus requires a space for toner cartridge replacement above, so that its installation site may be limited. When an image reading unit is provided on the top of the image forming apparatus, the toner cartridges cannot be removed from above, and the apparatus should undergo some design changes relating to toner cartridge replacement.